Advanced space transportation technologies

A wide range of propulsion technologies for space transportation are discussed in the literature. It is clear from the literature review that a single propulsion technology cannot satisfy the many mission needs in space. Many of the technologies tested, proposed, or in experimental stages relate to: chemical and nuclear fuel; radiative and corpuscular external energy source; tethers; cannons; and electromagnetic acceleration. The scope and limitation of these technologies is well tabulated in the literature. Prior experience has shown that an extensive amount of fuel needs to be carried along for the return mission. This requirement puts additional constraints on the lift off rocket technology and limits the payload capacity. Consider the possibility of refueling in space. If the return fuel supply is guaranteed, it will not only be possible to lift off more payload but also to provide security and safety of the mission. Exploration to deep space where solar sails and thermal effects fade would also be possible. Refueling would also facilitate travel on the planet of exploration. This aspect of space transportation prompts the present investigation. The particle emissions from the Sun's corona will be collected under three different conditions: in space closer to the Sun, in the Van Allen Belts; and on the Moon. It is proposed to convert the particle state into gaseous, liquid, or solid state and store it for refueling space vehicles. These facilities may be called space pump stations and the fuel collected as space fuel. Preliminary estimates of fuel collection at all three sites will be made. Future work will continue towards advancing the art of collection rate and design schemes for pumping stations

The Iraq War: killing dreams of a unified EU?

For students of EU public policy, the EU's reaction during and after the Iraq War may represent the same story of impotence that has historically plagued the EU when trying to speak with a single voice and act with a united front during a major world crisis. Despite some achievements with the EU's Common and Foreign Security Policy (CFSP) of the early 1990s (Ginsberg 1997; Holland 1995), the Iraq War perhaps best reflects Cameron's concerns: "in handling serious political crises, especially those involving armed conflict, the Union has rarely acted as one", or acted effectively (Cameron, 1998, 66). Seeking to better understand why the EU did not act effectively during the Iraq War and to consider what lessons can be taken from this experience, the paper has three main objectives. First, the paper considers the theoretical reasons that help explain why the EU has historically failed to create a common defence and security policy. The section thereafter analyses developments during the Iraq war and tests which theoretical explanations (or combinations thereof) are of most value to understand the EU's stance. The final section then considers the future of the EU as an international actor in light of the fundamental concepts introduced by Hill (1993) regarding 'capabilities' and 'expectations' of EU foreign policy

Neutrino Mass Matrices with Two Vanishing Elements/Cofactors

We study the phenomenological implications of the recent neutrino data for class B of two texture zeros and two vanishing cofactors for Majorana neutrinos in the flavor basis. We find that classes $B_{1}$($B_2$) of two texture zeros and classes $B_5$($B_6$) of two vanishing cofactors have similar predictions for neutrino oscillation parameters for the same mass hierarchy. Similar predictions for classes $B_3$($B_4$) of two texture zeros and classes $B_3$($B_4$) of two vanishing cofactors are expected. However, a preference for a shift in the quadrant of the Dirac-type CP violating phase($\delta$) in contrast to the earlier analysis has been predicted for a relatively large value of the reactor neutrino mixing angle($\theta_{13}$) for class B of two texture zeros and two vanishing cofactors for an inverted mass spectrum. No such shift in the quadrant of $\delta$ has been found for the normal mass spectrum.Comment: 15 pages, 10 figures and 3 table

Continuity and change in party positions towards Europe in Italian parties: an examination of parties' manifestos

This paper analyses Italian parties' manifestos for national and European elections from 1979 to 1999 with the 'Wordscore' programme in order to gauge whether party positions with regard to the European Union have changed and whether the salience of the European Union has increased. Results indicate that, although there is no sign of increased salience, the leading Italian political parties have repositioned themselves in their attitudes towards the European Union, indicating that the European political space matters for national parties

An experimental study of near wall flow parameters in the blade end-wall corner region

The near wall flow parameters in the blade end-wall corner region is investigated. The blade end-wall corner region was simulated by mounting an airfoil section (NACA 65-015 base profile) symmetric blades on both sides of the flat plate with semi-circular leading edge. The initial 7 cm from the leading edge of the flat plate was roughened by gluing No. 4 floor sanding paper to artificially increase the boundary layer thickness on the flat plate. The initial flow conditions of the boundary layer upstream of the corner region are expected to dictate the behavior of flow inside the corner region. Therefore, an experimental investigation was extended to study the combined effect of initial roughness and increased level of free stream turbulence on the development of a 2-D turbulent boundary layer in the absence of the blade. The measurement techniques employed in the present investigation included, the conventional pitot and pitot-static probes, wall taps, the Preston tube, piezoresistive transducer and the normal sensor hot-wire probe. The pitot and pitot-static probes were used to obtain mean velocity profile measurements within the boundary layer. The measurements of mean surface static pressure were obtained with the surface static tube and the conventional wall tap method. The wall shear vector measurements were made with a specially constructed Preston tube. The flush mounted piezoresistive type pressure transducer were employed to measure the wall pressure fluctuation field. The velocity fluctuation measurements, used in obtaining the wall pressure-velocity correlation data, were made with normal single sensor hot-wire probe. At different streamwise stations, in the blade end-wall corner region, the mean values of surface static pressure varied more on the end-wall surface in the corner region were mainly caused by the changes in the curvature of the streamlines. The magnitude of the wall shear stress in the blade end-wall corner region increased significantly in the close vicinity of the corner line. The maximum value of the wall shear stress and its location from the corner line, on both the surfaces forming the corner region, were observed to change along the corner. These observed changes in the maximum values of the wall shear stress and its location from the corner line could be associated with the stretching and attenuation of the horseshoe vortex. The wall shear stress vectors in the blade end-wall corner region were observed to be more skewed on the end-wall surface as compared to that on the blade surface. The differences in the wall shear stress directions obtained with the Preston tube and flow visualization method were within the range in which the Preston tube was found to be insensitive to the yaw angle

Force induced melting of the constrained DNA

We develop a simple model to study the effects of an applied force on the melting of a double stranded DNA (dsDNA). Using this model, we could study the stretching, unzipping, rupture and slippage like transition in a dsDNA. We show that in absence of an applied force, the melting temperature and the melting profile of dsDNA strongly depend on the constrained imposed on the ends of dsDNA. The nature of the phase boundary which separates the zipped and the open state for the shearing like transition is remarkably different than the DNA unzippingComment: 8 pages, 10 figure

High frequency Alternating Current (AC) tangent delta

Power cables are constantly subjected to thermal, electrical and mechanical stresses during their service life which leads to ageing of the insulation material. Ageing of the insulation means that the insulator degrades or gets older. When the insulation is degraded it does not have the same physical properties as compared to the new cables, which basically means that the risk of failure has been increased. So, it is necessary to carry out a diagnostic test to resolve the possible problem that may occur in cable insulation so that precautionary action can be taken to avoid unnecessary in-service failure of the underground cable [1]. Dissipation factor or tangent delta measurement in either time or frequency domain are used to identify water tree degraded XLPE cables with high moisture content or moisture ingression through poor jointing, diagnostic tests based on [2], [3]. In practice, standard laboratory electrical test equipment utilizing power frequency (PF) i.e. 50Hz to 60Hz testing is used. Hence, large static transformer was installed in the laboratory to cater any large capacitance test sample for high voltage testing. These existing tangent delta diagnostic test methods are bulk assessment technique that cannot sectionalize or pin point the water tree or any other conductive defect. In addition, both this tangent delta measurement technique which utilizes standard 0.1Hz and 50Hz equipment is not capable to extract the tangent delta values of accessories from the bulk assessment. It can only diagnose the overall condition of the complete cable system that includes cable, joints and terminations. Since medium voltage underground (MVUG) cables in utilities are in service for many years, it is crucial to develop a method to sectionalize or identify the defective components

Smart Meter Privacy: A Utility-Privacy Framework

End-user privacy in smart meter measurements is a well-known challenge in the smart grid. The solutions offered thus far have been tied to specific technologies such as batteries or assumptions on data usage. Existing solutions have also not quantified the loss of benefit (utility) that results from any such privacy-preserving approach. Using tools from information theory, a new framework is presented that abstracts both the privacy and the utility requirements of smart meter data. This leads to a novel privacy-utility tradeoff problem with minimal assumptions that is tractable. Specifically for a stationary Gaussian Markov model of the electricity load, it is shown that the optimal utility-and-privacy preserving solution requires filtering out frequency components that are low in power, and this approach appears to encompass most of the proposed privacy approaches.Comment: Accepted for publication and presentation at the IEEE SmartGridComm. 201